Adhesive composition with improved bonding strength and heat seal performance

1 . An adhesive composition, comprising:

(A) an acrylic emulsion polymer consisting of

(i) structural units of a vinyl aromatic monomer,

(ii) structural units of a (meth)acrylate monomer selected from the group consisting of methyl acrylate, butyl methacrylate, butyl acrylate, and combinations thereof, and

(iii) structural units of a (meth)acrylic acid; and

(B) a vinyl aromatic monomer-maleic anhydride copolymer,

wherein (B) vinyl aromatic monomer-maleic anhydride copolymer is present at an amount of 0.1% by weight to 6.5% by weight, based on the total solid weight of the adhesive composition.

2 . The adhesive composition of claim 1 , wherein the acrylic emulsion polymer consists of, by weight based on the weight of the emulsion polymer,

(i) from 30% to 50% of structural units of the vinyl aromatic monomer,

(ii) from 50-70% of structural units of the (meth)acrylate monomer, and

(iii) from 0.1% to 8% of structural units of the (meth)acrylic acid.

3 . The adhesive composition of claim 2 , wherein the acrylic emulsion polymer consists of, by weight based on the weight of the emulsion polymer,

(i) from 30% to 50% of structural units of the vinyl aromatic monomer that is styrene,

(ii) from 50-70% of structural units of the (meth)acrylate monomer that is butyl acrylate, and

(iii) from 0.1% to 8% of structural units of the (meth)acrylic acid that is acrylic acid.

4 . The adhesive composition of claim 1 , wherein the vinyl aromatic monomer-maleic anhydride copolymer comprises (a) structural units of one or more vinyl aromatic monomers and (b) structural units of maleic anhydride.

5 . The adhesive composition of claim 1 , wherein the vinyl aromatic monomer-maleic anhydride copolymer (B) is present at an amount of 0.5% by weight or more, and at the same time 6.0% by weight or less based on the total solid weight of the adhesive composition.

6 . The adhesive composition according to claim 1 , wherein the adhesive composition is a one-component water based adhesive composition.

7 . A method of producing a laminate using the described adhesive composition, comprising:

(a) providing the adhesive composition of claim 1 ;

(b) applying the adhesive composition on a first portion of a surface of a substrate to form a layer of the adhesive composition;

(d) bringing a second portion of a surface of a substrate into contact with the layer of the adhesive composition, so that the layer of the adhesive composition is sandwiched between the first portion and the second portion; and

(e) drying the adhesive composition or allowing it to dry.

8 . A laminate prepared by using the method of producing a laminate of claim 7 .

9 . A laminate comprising a first portion of a surface of a substrate, a layer of an adhesive composition of claim 1 , and a second portion of a surface of the same or a different substrate, wherein the layer of the adhesive composition is sandwiched between and in contact with the first portion and the second portion.